docs: def fincre(oldname):
      """Increment the synphot version number from a filename"""
      x=re.search('_(?P<version>[0-9][0-9][0-9])_syn',oldname)
      version=x.group('version')
      newversion="%03d"%(int(version)+1)
      ans=oldname.replace(version,newversion)
      return ans